Project Summary/Abstract This study investigates whether early, proactive intervention improves speech and language outcomes in infants at risk for communication disorders. Speech and language disorders are common and inflict high social, emotional, and educational burdens. Preventive treatments are not available; assessments and treatment are usually not initiated until ages 2 or 3 years when deficits manifest. Infants with classic galactosemia (CG) hold the key towards investigating proactive approaches because they are at high risk not only for motor and cognitive deficits but also for severe speech and language disorders. Because CG is diagnosed via newborn screening, the known risk can be leveraged to evaluate whether proactively supporting the acquisition of prespeech (2 to 12 months; cooing, babble) and early speech (12 to 24 months; first words, speech sound acquisition, vocabulary growth, sentence complexity) can reduce the communication deficits associated with CG. We designed and launched a proactive speech/language program called Babble Boot Camp (BBC) for infants with CG, ages 2 to 24 months. Initial results are consistent with a beneficial effect on speech and language development, but generalizing from a small pilot cohort is impossible. The proposed study enhances the power, scope, and impact of the BBC by implementing it in a larger CG cohort and evaluating it against control cohorts with and without CG. A pediatric speech-language pathologist implements the program via parent training. Parents learn about the typical milestones of prespeech, speech, and language development, potential red flags for delays, and importantly, activities and routines that support typical development for all stages of the program, for instance stimulating and reinforcing babble, shaping first words, and building vocabulary and sentence complexity. Longitudinal measures of coo, babble, speech, language, and linguistic environment using automatized daylong audio recordings in conjunction with signal processing software generate a rich, objective data matrix. To quantify indirect treatment effects, measures of cognition and quality of life are also collected. Formal testing of speech, language, cognition, and quality of life outcomes is performed at 24 months, with follow-up at 36 and 48 months. Using multilevel growth curve models, direct (speech, language) and indirect (cognition, quality of life) treatment effects will be evaluated longitudinally and through group comparisons in the three cohorts. Expected results will show that proactive services improve speech and language outcomes, providing objective evidence to change clinical management from deficit- based to proactive services. Indirect benefits for cognition and quality of life are possible. Results will motivate testing proactive approaches in infants with other risk types for speech and language disorders. This study has potential to enhance health and reduce disease burden associated with speech and language disorders. It fits a high NIH funding priority by developing and implementing treatment for intellectual and developmental disorders with the potential of improving quality of life and cognitive and behavioral manifestations.